Heretofore there have been many different tire constructions and tire designs proposed. A number of tire tread designs have also been proposed heretofore and some tire tread traction designs have provided directional tread surface operating characteristics therefor to improve tire tread traction performance. Various constructions of "tire carcasses" have been provided utilizing combinations of bias ply cords, radially directed cords, breaker strips, belt plies or the like but none have had any success as designed or patented, therefore none have been "reduced to production." One main problem that is encountered in all pneumatic tire service is that of the rolling resistance of the tire, and efforts have been, and are, continually being made to reduce the rolling resistance of pneumatic tires. It is a known fact that operation of a bias tire under load at increasing speeds causes a buildup or slight roll or ridge of the plastic rubber in the tire tread to be created immediately prior to the portion of the tread in road engaging contact. This little rib or roll of the tread is continuously changing as the tire RPM increases with vehicle speed, and such little rib or accumulation of rubber material from the tire tread is part of the reason why rolling resistance exists in tires and, obviously, the resistance to rolling of the tire is a negative factor insofar as operational mileage from the tire and/or vehicle on which the tire is mounted is concerned. It may be said that operation of the tire could be compared to the forcing or pulling the tire through a wringer since the tire is compressed under load and continually moves in relation to its support surface. Hence, this little roll or rib of rubber tread material that is formed just prior to the tire tread area contacting the road surface must be pulled down into a flat tread profile during road engaging contact.
One approach to improved tire constructions, to improved tire operational characteristics, and to improved riding characteristics, softness and comfort have resulted in the provision of a number of different tire carcass designs. One of such tire constructions is shown in U.S. Pat. No. 3,286,758, wherein the tire cords are primarily laid to extend radially of the tire carcass, but the tire cord plies are made of such length that the plies are folded up around a bead at each end of the ply. This causes the cords that were radially directed in the main portion of the ply to assume some small acute angle to a radial line, so that the two ends of the ply being folded up over the tire can be made of such length as to overlap each other at different bias angles for approximately the tread width area of the tire. Additionally, any suitable belt plies can be used in the tire, normally between the tire carcass and the tread portion of the tire. This cured tire construction contains both radial and bias positioned cord reinforcement plies. This radial and bias tire combination creates unequal internal cord stresses in the sidewall that are self-destructive in tire service.
Another approach to pneumatic tire carcass design, as proposed in the past, has used a split ply wherein only one end of the cords in any given ply are secured to one bead and the other ends of the cords in the ply are, in effect, freely floating in the tire. One representative construction of this type is shown in U.S. Pat. No. 2,703,128, and other illustrations of such type of split plies in tires are shown in U.S. Pat. No. 2,703,132. However, in both of such prior patents, the cords in the sectional plies that are diagonally or circumferentially adjacent each other, extend in the same or parallel direction so that the two sets of cords provided in two different and adjacent plies, and where the cords are in overlapped axial relationship to each other, do combine when overlapped to form a continuous ply extending from bead to bead of the tire.
As indicated, even though there have been a large number of widely different types of tire carcass designs proposed and patented, none have been "Reduced to Production Practice" for the marketplace and there are no bias tire carcass constructions available at this time wherein the tire carcass can really provide similarly improved operational benefits, and reduced rolling resistance in the tire, especially when rotated in the preferred direction, as determined by the tire and carcass design.